The evolution of computer technology has created a need for computer systems that can also process various audio and/or informational inputs. The use of computers to process audio signals has become known in the art as a "multimedia" PC or a "multimedia environment." In a multimedia environment, audio signals from various input sources are typically summed and communicated to common output devices. Discrete analog components are typically utilized which provide for controlling the relative volumes of the input signals, summing the input signals together, processing telephony signals and information, and outputting the aggregate signals in the desired format.
The use of discrete components to control audio and/or other informational signals has significant drawbacks. Many new multimedia applications require lower component cost, higher utilization of circuit board space and higher reliability. In addition, the use of discrete components often loses critical functionality and flexibility. Moreover, several types of audio signals either originate with or are controlled via a computer network. Discrete analog components can not be easily interfaced with computers to produce consistent and high quality results.
Therefore, a critical need exists for a system that would provide computer programmed volume and summing control, along with information processing in a compact fashion. A need also exists for a system capable of receiving and processing inputs from telephony systems, CD-ROM (compact disk-read only memory) analog storage devices, line-in sources (such as from audio tape), FM (frequency modulation) synthesizers, microphones, and PCM (pulse code modulation) sampled sounds, and which can combine each of these inputs in a desired way. A need also exists for a system capable of providing outputs for PCM sampled sound, telephony systems, and stereo line-out, so that the outputs can be put to use in the multimedia environment. Due to extensive use of computers, a need also exists for a system that can be digitally controlled through an external computer network under register control. The present invention fulfills each of these needs.